This invention relates to an automatic high-speed document verification system and, more particularly, to a document verification system which utilizes optical scanning techniques to detect subtle variations in patterns printed on documents.
Checks, stocks, bonds and the like are often encoded to assure that they are valid documents and not fakes or photocopies. Prior art verification schemes include printing a message, such as "void", on the document with ink visible only under ultraviolet light. Another verification system involves printing a pattern on the document. This pattern includes lines of varying widths. Although the pattern looks continuous to the human eye, a photocopier cannot detect the thinner lines of the pattern. If the lines are properly arranged, a photocopy of an invalid document will have a blank portion which may be in the shape of word, e.g., "void", or an icon.
Both of these prior art systems are currently produced by Moore Business Forms. These systems are manual and therefore require a prohibitive amount of time to verify a large number of documents. For example, the photocopying system requires that each document be copied and the copies visually inspected. Because of this time constraint, the documents (for instance checks) cannot be verified until after they have already been honored because it would take too long for each document to be verified prior to honoring it. Thus, the prior art verification systems can only be used as an internal control to ensure the validity of documents after they have already been honored.
High speed check handling equipment is also known in the art; for instance U.S. Pat. No. 4,523,330 to Cain and the UNISYS Reader Sorter DT. These devices create a video image of each check to be processed. The data on the check's image may then be forwarded to an operator to verify payment.